Apple Motion 3 - Manual (Page 207)

Chapter 2 Creating and Managing Projects 207
The image is scaled—the equivalent of using the Transform tool to scale down the
image in the Canvas while pressing Shift. To observe that the image is merely
transformed and has not changed resolution, select the image file in the Media tab of
the Project pane, and then display the Media tab Inspector. The Fixed Width and Fixed
Height parameters display the resolution of the original file.
The image is scaled to fit the largest X or Y value of the image to that of the Canvas.
Down-Res to Canvas Size: This setting changes the resolution of the imported image
so that the image fits the project size while maintaining its aspect ratio.
Note: The Down-Res to Canvas Size option is the best choice for optimizing your
process time. When you use Scale to Canvas Size, Motion must calculate the scale at
each frame.
In the following example, a 1309 x 2020 JPEG image is imported into an NTSC
Broadcast SD project with Down-Res to Canvas Size selected in Preferences.
The original image resolution remains unchanged.